Police keeping open mind after possible poisoning near Salisbury

Neil Basu, Britain's most senior counter-terrorism officer, said initially a 44-year-old woman collapsed and an ambulance was called to a residential address in Amesbury about 10:15am on June 30.

Officials did not say why they had waited four days to declare a "major incident".

Conservative MP Tom Tugendhat, chairman of the Foreign Affairs Committee, said the use of a deadly nerve agent in Salisbury was an "absolutely vile act of terror".

The hospital is where the Skripals also spent weeks in a critical condition before slowly recovering and being discharged.

Mike Wade, a regional health protection director for Public Health England, said late on Wednesday that there was "no significant health risk to the wider public" but officials planned to keep their advice under review as the police investigation continued.

The exposure of two people apparently unconnected to espionage or Russian Federation has sparked fears that traces of the nerve agent remain in the area.

Russian Federation has said it does not possess such nerve agents, did not develop Novichok, and President Vladimir Putin dismissed as nonsense the notion that Moscow would have poisoned Skripal and his 33-year-old daughter.

He went on: "The hostel (where Ms Sturgess lived) now becomes a crime scene and they will treat that with the utmost respect".

By lunchtime, Scotland Yard releases a short statement making clear that, "as you would expect, given the recent events in Salisbury", officers from the counter-terrorism network are now involved in the investigation.

Affected sites include Amesbury Baptist Church, which had police standing guard at the entrance on Tuesday. The other location has not been disclosed.

Scientists at Britain's defence laboratory at Porton Down are carrying out tests to try and establish if there is any connection between the two incidents, British media reported.

She also urged people not to pick up any "unknown or already unsafe objects such as syringes".

"I also want to highlight that the areas at Salisbury already cleaned back in use like the Maltings are safe", he said.

Asked if the pair may have been deliberately targeted, Basu said: "That is a theory but it's speculation at the moment".

"There is nothing in their background to suggest that at all".

This latest case of poisoning has raised public health concerns in the Salisbury area, where a massive decontamination effort took place after the Skripals were poisoned.

Investigators have yet to determine how Sturgess and Rowley came into contact with the nerve agent, but they've closed down sites in Amesbury and Salisbury where the victims are thought to have traveled before they were found sick.

Salisbury District Hospital is open as usual and is advising people still to attend routine appointments unless they are contacted to state otherwise. Officers are still working to identify their next of kin.